Biology - Chapter 9 and 10 Flashcards
What is genetic diversity and how is it measured? How does a larger gene pool affect a population?
Refers to amount of genetic variation that exists between individuals. Is measured by reference go the populations gene pool which is the sum of all off the different genes and alleles present in a population and species. The larger of more diverse a populations gene pool, the greater the populations resilience to environmental change.
Types of sexual reproductive strategies
- Location of embryonic development
- Number of offspring produced per reproductive cycle
- The amount of prenatal care invested in each offspring.
What is oviparity?
When eggs are released to the external environment. The organism grows with little development inside the mother.
What is viviparity?
When the embryo develops inside the mothers body and is born after a period of gestation. Fertilisation occurs inside the mother.
What are advantages of sexual reproduction?
- Increases genetic diversity of a population by allowing for recombinant offspring
- Improves disease resistance by promoting the presence of different alleles
- combing the genetic material from 2 gametes reduces chances of an offspring inheriting a genetic disorder that might be carried by 1 parent
What are the disadvantages of sexual reproduction?
- the cost of male progeny
- the time, energy and resources it takes to attract and find a mate
- the risk of transferable disease associated with sexual intercourse
- the risk of losing offspring to outside influences such as embryo damage
How does pollination occur?
Angiosperms reproduce through pollination which is when pollen is collected by the stigma of the flower and fuses with the ovule. Then the embryo that develops with become a seed which contains nutrients to for an immature plant to bean to grow into a new plant under the right conditions.
What are the two categories pollinators can be?
Biotic - organisms that are attracted to brightly coloured petals, inviting smell and nutrient rich nectar
Abiotic - non living methods such as wind or water, allowing plants yo focus on maximising pollen dispersion then attracting pollinators.
Types of asexual reproduction
- binary fission
- budding
- fragmentation
- vegetative propagation
- sporogenesis
- parthenogenesis
What is binary fission?
A type of asexual reproduction where one organism divides into two identical organisms
What is budding?
A type of asexual reproduction where a group of cells form a bud and break away from the original organism to form a clone
What is fragmentation?
A type of asexual reproduction where a parent organism breaks into fragments each of which may develop into individual clones
What is vegetative propagation?
A type of asexual reproduction where a plant grows from fragments such as stem or toot cuttings of its parents
What is sporogenesis?
A type of asexual reproduction where spores form on the surface of the organism and are dispersed into the surroundings where they may develop into individual clones of the original
What is parthenogenesis?
A type of asexual reproduction where an embryo can develop from a single unfertilised gamete
Advantages of asexual reproduction
- asexually reproducing populations grow faster
- offspring are identical clones of parent - good for phenotype that is fine tuned to survive in that particular environment
- does not require an organs to find a mate (doesn’t need to be mobile)
- required little parental investment (removes need to protect offspring)
Disadvantages of asexual reproduction
- genetic diversity is low - therefore may suffer during rapid environmental change
What are the 2 types of reproductive cloning technologies in animals?
Somatic cell nuclear transfer and embryo splitting
Describe the stages of SNCT
It involves two different cells: a donated egg cell and a donated somatic cell from another animal
Stages are:
1. Enucleation – the removal or destruction of the nucleus from the donated egg cell to produce an enucleated egg cell.
2. Extraction – the donated somatic cell’s nucleus is extracted.
3.Insertion – the somatic cell’s nucleus is inserted into the enucleated egg cell.
4.Development – following insertion, the cell begins to divide and develop into an embryo, which is then implanted into a surrogate mother. The pregnancy then continues as normal.
In this process, the offspring produced is genetically identical to the donated somatic cell as they both contain the same nucleus and genetic material.
Complications of SNCT
- Animal suffering
- Human cloning (mass destruction of egg cells and embryos from failed attempts)
- Premature ageing
Explain embryo splitting
The division of an early embryo unto several individual embryos.
Stages:
1. Fertilisation
2. Early embryo (morula and is totipotent)
3. They are implanted into surrogate mothers
4. This produces genetically identical offspring
Complications of embryo splitting
- alteration of embryos
- decreased genetic diversity
- they become research animals
What are the reproductive cloning technologies in plants?
- Plant tissue culturing
- cutting
- grafting
What is plant tissue culturing/micropropagation
The cloning of plant cells on a nutrient culture medium in a controlled environment. A callus then forms which can be separated into several cultures and stimulated to grow into clones of the original plant
What are plant cuttings
The growth of plants using a fragment of the original
What is plant grafting
The attachment of two individual plant stems together (one is the scion and this is connected to a developed root system called the rootstock)
Advantages and disadvantages to plant cloning
advantages: provide plants with cold tolerance, resistance to disease and increased productivity
disadvantage: reduction in genetic diversity - more susceptible to disease, pests, and environmental change
Abiotic factors examples
- temperature
- humidity
- rainfall/water availability
- sunlight
Biotic factors examples
A living organism that affects another organism in its ecosystem. Examples include plants and animals that the organism consumes as food, and animals that consume the organism.
Animal adaptation to desert: thermoregulation
the homeostatic process of maintaining a constant internal body temperature. In hot deserts, organisms have generally adapted to maximise heat loss, minimise heat gain, maximise water uptake, and minimise water loss. Organisms exchange heat with their environment through radiation, conduction, and convection. They also produce their own metabolic heat and release heat via evaporation. Organisms obtain water by drinking, eating food, and metabolic water production. They lose water through excretion and evaporative water loss (sweating).
Structural adaptions in animals
- insulation
- SA:V
- metabolic heat
- surface blood flow
- increase water input
- decrease water output
- evaporative cooling
How does insulation help an animal
More insulated = harder for animal to release heat into environment
Less insulated = easier for an animal to release heat into environment
Have evolved thickness of fur
Affect of SA:V (Structural)
High SA:V absorbs a proportionally large amount of heat in little time, allowing body temp to change quickly. Beneficial in hot climates if you release heat into a cold microclimate but direct sunlight will increase body temp.
Low SA:V releases or absorbs proportionally low amount of heat and their internal body temp is resistant to change. May be beneficial for an animal if exposed to direct sunlight or cannot avoid heat.
Affect of metabolic heat (physiological) - endotherms/ectotherms
Endotherms - speed lot of energy producing metabolic heat (in desert need effective strategies to release excess heat).
Ectotherms - obtain heat from environment so they can use energy on other processes (finding a mate/food, etc). Hence why more ectotherms in hot environments.
Affect of surface blood flow (physiological)
Vasoconstriction - to conserve heat
Vasodilation - to reserve heat
How to increase water input
- from food
- from dewfall
- metabolic production of water during aerobic cellular respiration
How to decrease water output
- Long loop of henle
- uric acid
Evaporative cooling
Release heat through evaporative cooling (sweating and panting). requires water so can lead to dehydration in hot climates.
Evaders and endurers (the 2 types of behavioural adaption)
Evaders: modify behaviours to avoid extreme temperatures and high internal body temps
Endurers: do not avoid extreme temps - seek shade or go into burrow - dig small pits to lay into, shade under trees
How do plants decrease heat uptake
- have lightly coloured or reflective leaves
- smaller surface area leaves
- orientating leaves vertically to minimise surface area exposed to sun
How do plants increase water uptake
- from absorbing water through roots (deep root systems or spread roots horizontally to absorb max amount of water for later use)
How does water storage affect plants
- some plants store lots of water during rain season and save for dry season
Factors affecting organisms in cold environments
- low temp
- piercing winds
- low nutrient availability
- precipitation as snow
4 ways of heat transfer
- radiation (reflect heat radiated back to body)
- conduction (in contact with solid)
- convection (in contact with air/water)
- evaporation (heat loss because water takes heat energy as it turns into gas)
4 ways of heat transfer
- radiation (reflect heat radiated back to body)
- conduction (in contact with solid)
- convection (in contact with air/water)
- evaporation (heat loss because water takes heat energy as it turns into gas)
Structural adaptation (insulation)
Thick insulating layer - thick fur, plumage, or subnormal fat
Structural adaptation (SA:V)
Low SA:V = easier to maintain constant internal temp with cold environment
Physiological adaptation (endotherms vs ectotherms)
More ectotherms in cold environment as animals can’t obtain heat from environment with lower temp than their body so maintaining a stable body temp via internal metabolic processes is advantageous.
Physiological adaptation - torpor
two types: hibernation (endotherms) and brumation (ectotherms)
Physiological adaptation - circulation
To prevent heat loss from blood: vasoconstriction (narrowing of the blood vessels) and countercurrent circulation (heat transfer method where seperate components of circulatory system flow next to each other in opposite directions.
Behavioural adaptation - reducing exposed surface area
Animals reduce SA:V by hiding or protecting their peripherals as temps drop. (curl up, stand on one leg)
Behavioural - huddling
decreases individual SA:V, decreasing amount of heat released
Behavioural - seeking shelter
animals surround themselves with little/no wind and more forgiving temps making them survive in colder weather
Behavioural - migrating to warmer climate
easier for breeding and raising newborns, more access to food and water
How does freezing temps affect plants
- enzyme and protein driven reactions progress slowly at low temps.
- formation of ice crystals within cell can rupture cell membranes
How do plants prevent freezing
- Modify lipid and chemical composition of cell membranes to increase functioning in low temps
- produce antifreeze proteins
Plants in cold environment - deciduous trees
Drops all leaves at once to avoid harsh conditions. advantages:
- avoid frozen leaf tissue
- require less energy + water in winter
- less branch breakage in high snow and winds
Plants in cold environment - seed dormancy
Is unable to germinate during specific tine under certain environmental conditions. seeds are dispersed before winter months then remain dormant until warmer weather
What is an ecosystem
All biotic factors + all abiotic factors + all the interactions between them
What is a population
group of organisms of the same species living in same geographical region
What is a community
group of interacting populations of different species in same geographical region
Population growth model
future population size = initial pop size + births - deaths + immigration - emigration
What is carrying capacity
Max population that an environment can sustain
R selection
- quick and many strategy
- large amounts of offspring regularly - no parental care/investement
- boom and bust - large increase in population followed by large decrease
K selection
- slow and few strategy
- smaller numbers of offspring - larger in size + more dependent on parental care
- reach sexual maturity later = less breeding time in lifespan
Population distribution
- uniform
- random
- clumped
refers to geographical spread across different areas
Population density
- number of individuals in population per unit area
effects availability of resources
Density independent factors vs density dependent factors
independent = factors unaffected as density changes (climate, natural disasters)
dependent = properties that change with density (availability of resources, disease, predation, accusation of waste)
What is symbiosis
An interaction between 2 organisms of different species living in close proximity to each other
Types of symbiotic interactions
- mutualism (+/+)
- commensalism (+/0)
- predation (+/-)
- parasitism (+/-) - obtains nutrients at expense of host
- amensalism (0/-)
- competition (-/-) - interspecific competition: competition for resources between 2 things of different species. intraspecific: competition between same species for resources
Keystone species impact
- species whose effe its on ecosystem are greater than expectable relative to its population size
- help give ecosystem structure and stability
- roles usually are apex predators (no natural predators and top of food chain) and ecosystem engineers (creates, significantly alters or maintains structure of environment
